1. Field of the Invention
This invention relates to a method and apparatus for generating and introducing acoustic signals into a low pressure chamber of a pressure regulator or governor mounted within a piping system, without breaching the piping system or interrupting flow through the piping system.
2. Description of the Prior Art
U.S. Pat. No. 3,055,209 discloses a method and apparatus for locating gas leaks in underground pipes. A speaker is positioned at one end of a branch pipe, which is in direct communication with a main pipe. A transducer is used to pick up sound waves emitted by the speaker and an amplifier and an indicator are used to detect the location of a pipe or a pipe leak by measuring the sound intensity from ground level. A disadvantage of the teachings of the '209 patent is the need for direct communication between the branch pipe and the main pipe, thus requiring shutdown of the main pipe to safely connect the speaker. Such method creates environmental, health and safety hazards.
U.S. Pat. No. 3,170,152 discloses an apparatus for detecting leaks in underground piping systems. A probe is inserted into an excavated hole to establish contact with a pipe. A transducer is positioned on one end of the probe and the probe is moved about various locations along the pipeline until a signal other than ambient noise is detected.
U.S. Pat. No. 3,264,864 discloses a process and apparatus for detecting gas leaks in underground pipes. A transmitting station is used to introduce sonic frequency signals into a main gas conduit, through a branch pipe which operates at the same pressure as the main line. The transmitted signals are detected at a portable transducer which is located at a receiving station that is coupled to the earth's surface, at different locations. The sonic pressure wave generated in the gas line results in the transmission of a mechanically excited sonic wave which escapes through a leak in the pipeline, into the earth. Such sonic wave can be detected by the transducer.
U.S. Pat. No. 4,013,905 discloses an apparatus for receiving acoustic signals from an underground pipe. The acoustic signals are transformed into electrical voltages which are fed into a computer. U.S. Pat. No. 4,172,382 discloses a laser interferometer system for detecting leaks and corrosion in underground pipelines, pressure containers and other metallic structures.
U.S. Pat. Nos. 3,967,282 and 4,062,010 disclose processes and apparatuses for detecting underground pipelines with an electrical impulse source which transmits a radar-type signal through an antenna into the ground. The radar-type signal is then reflected by a target. U.S. Pat. No. 4,600,356 discloses a process and apparatus combined with an excavation device for alerting an operator of an underground obstruction, particularly an elongated conductive object, such as water pipes and electrical cables. U.S. Pat. No. 4,649,948 discloses an apparatus and process for installing a Wye device within a pressurized pipe. The device includes a system for inserting a probe into a pressurized pipe for detecting leaks within the pipe.